Schematize Display system properties

Properties accessed across partitions are now schematized and will
become APIs to make explicit interfaces among partitions.

Bug: 117924132
Test: m -j
Change-Id: I4b49ed7e9b93c20855928ca61f9f128a0aa1d6d1
Merged-In: Id9bbb997669b05b6edb5307d561e766ead19abf1